This invention relates to a water repellent fabric and to a process to produce a water repellent fabric.
Water repellent treatments in the prior art include polysiloxanes such as those taught in U.S. Pat. Nos. 3,038,821 and 4,287,261. Such water repellent treatments result in a wash-fast treatment which permits the treated fabric to breathe, but require relatively expensive polymers as starting materials. Other water repellents known in the art include waxes, aluminum soaps, zirconium salts, quaternary ammonium salts, N-methlol fatty acid amides, diisocyanates and triisocyanates. These treatments have a variety of shortcomings which include high cost, and degradation of fabric softness and texture.
Rubbers, such as butyl rubbers, isoprene rubbers, and block copolymers of styrene and conjugated diolefins, are known as treatments for fabrics, but they have generally been used to provide a waterproof coating treatment which does not allow the fabric to breathe. Such coating is described in U.S. Pat. No. 4,696,830. Coating a fabric with rubber alters the surface texture of the fabric and makes the fabric stiff and uncomfortable to wear. Rubber coated fabrics therefore are not acceptable as a water repellent treatment. When the treated fabric must have a soft texture and a good feel to skin. This good feel to skin is commonly referred to as a good "hand".
It is an object of this invention to provide a process to treat fabric utilizing functional group containing hydrophobic elastomeric polymer which results in a water repellent fabric having an excellent hand. It is a further objective of this invention to provide this process wherein the treatment is not removed by repeated detergent washings. In another aspect, it is an object of this invention to provide a water repellent fabric with an excellent hand wherein repeated washings does not remove the water repellent nature of the fabric.